Art of casting steel car-wheels.



' x0 monnn.

- No. 728,956. PATENTED MAY 26, 1903.

T. MITCHELL.

ART OF CASTING STEEL OAR WHEELS. APPLICATION TILED AUG.'11,'1902.

2 SHEETS-SHEET 1.

PATENTED MAY 26, 1903.

T. MITCHELL.

ART OF CASTING STEEL GAR WHEELS.

APPLICATION FILED AUG. 11, 1902.

2 SHEETS-SHEET 2.

H0 MODEL.

f/w'zz/w INYENTOR:

WITNESSES:

, metalwas charged to the mold, a certain UNITED STAT-Es Patented May 26, 1903.

' PATENT [O F-ICE.

THOMAS MITOHEI L, or oHEsTEE, PENNSYLVANIA, ASSIGNOR TO DANIEL EAGAN, on PHILADELPHIA, PENNSYLVANIA.

ART OF CASTING STEEL CAR-WH EELS.

, srncmcanon forming part Letters Patent No. 728,956, dated May 26, 1903.

Application'llled August 11,

To all whom, it may cancel-m.

Be it known that'I, THoMAs MITCHELL, a

of which the ,following is a specification. v

Myimprovement relates to the artof moldiug or casting steel car wheels. when attempts have been made to cast car wheels ofisteel, it has been foundnec'essary to provide the molds, at points in'the vicinity of the rims, with openings leading to the exterior of the molds, so that when the molten portion of it'could flow out through said openlugs, to the end that, as the metal within the mold began to set,'the setting being, of course, .accompanied by considerable shrinkage,- -the metal whichhad so passed out marginal portiens ofi'the mold sioued by such shrinkage, *5

could flow back into any vacant spaces in the thus compensating'for the shrinkage, the metal returning through said openings becoming integral with the-metalof the partly set casting.

Q In this practice, however, such of the meta pass-ingout through the openings as did. not

return to the interior of the mold, of course,

- that when the wheel was removed from the mold,it;was necessary to such heads, a matter requiring considerable manually'remove time otwcrkmen.

- eratiens' of casting, e

an improvement in the methodsorart of cast- 7 my improvement con-J platingnot only'the-icouducting oftherations insutih manner. as to avoidt-hestence onprese'uce of "sink heads on the mass s" pacity Ito resist wear than 'teforeh n;possi'ble.. i

' Hitherto,

space occa-.-

sink heads or protuberances on" the side fa'ceof the wheel, with the result a ii th rm' re, the pr ction of om'pa'ct texture, and there-l 4 the sand of the lower end of the gate and that iof the drag,-the' ends of said corefiudingiu 1902. Serial No. 119,162. (No modeL) In the accompanying drawings I show an apparatus for molding or casting steel car wheels by the-aid of which my improvement in the art may be readily and conveniently practiced; Variations in the form of the apparatus employed may, of course, be resorted to without departurefromthe. spirit of my invention. e

In the accompanying drawings,

Figure l is a vertical sectional view of a flask showing a wheel cast therein.

- Figure 2 is a plan view of the device shown -in Figure 1, the cope of saidflask being reproved to show the upper face of the cast wheel, and the contractible chill inclosing' the same. A

Figure 3 is a plan view of the device shown in Figure 1.

Figure 4 is a fragmentary sectional view taken on the line 4-4 of Figure 1.

Similar letters of reference indicate corresponding parts. 1 In the accompanying drawings,

a is the cope, and b thedrag of a mold which I'in'ay employ. a is a chill-shown as of the contracting variety. I illustrate a special ar rangement of gate through which the molten metal is supplied to the interior of the mold.

The gate is preferablystraightand extends vertically acousiderabledistance, preferably two feet or thereabout above the top of the cope, and may be provided at its upper end with any usual funnel-like mouth to the more conveniently re'ceivemolten metal. I

The gate is'com osed of au-external tubelikeimet'al body'ii' the lower end of which rests n pon the'central'split ring e, of the cope, which is integrally connected by the series of radially disposed webs c, with the external rimor shell of the eope. The sand or other lining f of the gate is continuous of the mass of sand gof the cope. I

h isa core arranged centrally within the mold space, having a central opening registering with the channel of the gate, the con tr al opening or bore of the core and the channel or bore of'the gate coustitutiuga contin- .uous channel.

. Said core h is conveniently held between said sand suitable seats for themselves. The core h happens to be illustrated as of a different textureof sand from that of the cope and gate, and in fact I so prefer to make it Said core k may, however, manifestly be made of the same character of sand as that em-'-' ployed in the cope and body of the gate, and be made as a part or continuous of the mass of sand in said cope and gate. I

j are ports or channels, formed in the sand of the drag, beneath the core h, through which the molten metal passing downward through the gateand core, emerges into the lower part of the mold space.

The contracting chill c is of a well known character and I make. no claim upon it in itself, nor do I deem it necessary to describe it. Said chili is, as illustrated in Figure 1, preferably temporarily, attached, by suitable bolts m, to the cope.

In carrying out or practicing my invention by the aid of the apparatus described, Icharge the molten metal within the upper end of the gate, whereupon said metal will descend through the gate and the bore of the core, and the necessary quantity emerge throughthe channels j to the lower portion of the mold space, the metal being charged to the gate in such quantity that after the mold spacehas been filled a column of the metal will remain in the channel of the gate.

The metal accumulating-in the bottom of the mold space rises and [lows laterally without splashing or destruction of the mold, and in due time completely fills the mold space, which latter may be provided with sink heads for the hub of the wheel.

By reason of the elevation of the gate the metal enters and remains in the mold space under such pressure that said mold space is very uniformly and thoroughly filled with the molten metal, the pressure of the column acting while all the metal in the mold is still fluid to very thoroughly compact the metal throughout all the mold space.

As the entire bodyof metal forming the body of the wheel passes in a molten condition down through the gate and core in its passage to the mold space, it communicates a considerable part of its heat to the sand adjacent to the channel of the gate and core, and the heat thus stored in said sand, after the charging operation is completed, acts to retain the metal in the core and gate in a'fluid condition fora considerably longer time than would be the case'were such metal not acted upon by the heat from the sand.

The column of metal thus remaining fluid,

operates, under well-known physical laws, to exert pressureagainst the metal in the mold space.

So soon, moreover, as the metal adjacent to the central portion of the mold space, that is to say, the portion in the,vicinity of the hub of the wheel, in setting, begins to 'contract, the molten metal from the column onters the mold space and unites with the metal of the wheel casting in the portion referred to to compensate for the shrinkage.

The metal of the central portion of the wheel casting will, therefore, not onlyremain under the considerable pressure of the column while molten and in the early stages of the setting operation, whereby its metal will be compacted and consolidated, but such shrinkage as occurs will be compensated for by the entry, under pressure, of the molten metal from the column, which last-mentioned column, as stated, is retained in a moltencondition for a considerable time. l

The central portion of the wheel, therefore,-

will be of full contour and of compacted and consolidated texture.

The metal of the rim portion of the wheel, making contact with the metal chill very quickly communicates a portion of its heat to the said chill.

The heat thus communicated to the contracting chill, consisting in the form shown of an outer ring, an inner sectional ring-shaped portion, and diagonally disposed stems, occasions the movement of the inner sectional ring-shaped portion of said chill toward the wheel casting, thus following up the contracting metal of the casting and hearing or pressing upon the rim face of said casting, making said rim perfectly circular and smooth so as to entirely obviate the use of machine work,

heretofore required for finishing such rims.

As a result of the compressive action of the chill upon themetal of the rim portion of the wheel casting, said metal is in its setting maintained in'a compressed and consolidated condition, with the result that the rim portion'of the wheel is of more solid and compact texture, than if made with sink heads as heretofore.

The position of the elevated gate at the central point of the flask, in which position the metal passes" down a straight vertical channel through the cope and directly into the mold spaee',is a feature of great importance, iu'asmuchas the pressure due to the elevation of thefgate thereby acts directly upon the metal; within the mold and it is not lost or wasted in traveling a considerable lateral distance before reaching the interior of the mold as would be the case were said gate situated at a point outside of the rim of the mold.

Furthermore, by reason of said location of the elevated gate, the molten metal has the IIO minimum distance to travel to reach the mold space, and consequently reaches said space with the maximum fluidity, and, furthermore,

in my arrangement, the pressure against the It will be observed that I employ a hydrostatic head of metal of considerable height,the

height in practice being not less than fifteen inches above the mold space, and preferably -omy in the art.

about twenty-four inches, and that I combine therewith a contracting chill of such a construction that it contracts over a, wide range,

and therefore has' a multiplied action. The combined compressive efiect on the metal of a head of the above dimensions and of a chill The dispensing with the heads constitutes a very great practical improvement and econ Haviug thus described my invention,

1. The improvement in the artof molding or casting steel car wheels, which consists in conveying to.a mold space of suitable form,

between a cope and a drag, a snificient quantity of molten steel, and compacting the metal as it sets by subjecting it to a hydrostatic head of metal of considerable height, and to a circumscribing chill having a multiplied action, which tends to move towardthecenter of the apparatus, and thus exercise compressive action'upon the metal, whereby a solid wheel is produced without the use of a head-.

ing or headings upon the rim,

2. The improvement in the art of molding or casting steel car wheels, which consists in conveying to a mold space of s itable forth, between a cope and a drag, a su cient quantity of molten steel to fill the mold, and compressing and compacting the metal as it sets by subjecting it to a hydrostatic head of metal of considerable height, and to a circumscribing contracting chill having a-multiplied-action which tends to move toward the center of the apparatus and exercise compressive action upon the metal, maintaining it in proper shape as it contracts in setting, and thereby producing a wheel which is dense, firm and of sharp outline, without the use of heads.

3. The improvement "in the art of casting steel car wheels, which consists in conveying through a gate or channel to a'mold space of suitable form, a charge of moltensteel suflicient to fill said mold space, and in maintain 1 ingin communication with i the central por- .tion of the metal within the mold space, a verticallyextending hydrostatic head of metal of. considerable height arranged within said gate or channel, saidhead being arranged ercise compressive action upon, the metal,

whereby themetal of the casting is, as it sets,

compressed, added specified.

* 4. The herein described improvement in the art of molding cast steel car wheels, which consists in charginglfrom a point vertically above'the central part of a mold through an elongated channel having direct connection with the lower sideof said mold, a quantity of moltensteel to said mold, and causing said molten metal to gradually rise and fill the mold and the channel, and forming in the channel a hydrostatic head of metal of a heightnot less than fifteen inches, and compressing the metal in the mold by the action of said head,-and adding to the metal in the mold space from the metal of the head as the metal in the mold space sets, and compressing and compacting the metal by acircumscribing contracting chill having a-multiplied action, whereby a cast wheel. is produced which is dense, firm, and of sharp outline.

5. The herein described improvement in the art of molding cast steel cal wheels, which consists in charging molten steel to a mold from a point vertically above'the central part of the same, through an elongated channel to, andconsolidated, as-

having direct connection with the lower side of said mold, and causing the molten metal to gradually rise and fill the mold and the channel, to' form a hydrostatic head of metal of considerable height inthe said'channel, and compressing the metal in the mold by the action of the said head, and adding to the metal in the mold space from the metal of the'head as the metal in the mold space sets, and also compressing and compacting the metal in the mold by a circumscribing contracting chill havfing a multiplied a'ction.

In testimony that I claim the foregoing as my invention I have hereunto signed-my name this;8th dayof August, A. I). 1902.

' I THOMAS MITCHELL. t In presence of Tnos. K. LANCASTER, I ARTHUR E. Pawn. 

